How much improvement should I see in mpg after breakin period on new 5.4L?? I
 

I put 270 miles on my truck in 3 days and filled here then filled her up. After calculating numbers because tank wasn't completley empty when I filled I averaged 14.4 on first tank. Not bad but not good just wondering how many more miles if ANY my truck will get after its broken in?? Thanks

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2001 F-150 5.4L trition,
Regular cab with 8' bed
XLT with Black Clearcoat
4x4 3.55 limited slip
factory cab steps
class III tow package
Factory ordered: 12/5
recieved: 2/22

I'm getting 19 mpg now with my 5.4L. My guess is that you will gain about 2 mpg after break in. You can add a tonneau cover and get another 1 or 2 mpg.

I get less than that almost all the time with about 50% highway driving.

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2000 F150 XLT 4x4 Short Bed. Amazon Green, 5.4L, SuperCab, ORP, Tow Package, Sliding Rear Window, Electronic Shift, Keyless Entry, LT265-70-17 Tires, Clarion Pro Audio, Herculiner Bedliner, Air Silencer Removed.

1994 SVT Mustang Cobra. #1032 of 6009. Black coupe with black leather int., 3.73 rear, Bassani Exhaust, Aluminum D/S, Bridgestone RE-71 255-45-ZR17

My Home Page

Had mine for nearly two years now. I didn't notice a 'break-in' increase. I do notice a summer winter change though.
My driving is 75% highway:
Winter 16.8 mpg
Summer 18.4 mpg
Towing boat (summer,60mph,3400lbs) 14.00 mpg



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1999 Ford F150 Lariat RegCab shortbed 5.4L 3.55LS Towpkg Line-X
15.714@85.21

Increase after break-in? None. The looser the engine gets, the more you're gonna want to stomp on the gas pedal. https://www.f150online.com/f150board/wink.gif

19mpg lucie? holy cow! do you drive strictly downhill? we should swap engines lol

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1998 xlt off road 5.4lsupercab auto pacific green clearcoat power drivers seat, keyless remote with factory alarm, tow package

It is not going to be a night and day difference. Under the same conditions, slightly better.

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My Ride: 1998 F150 4x4 Lariat Supercab Flareside 5.4L in Oxford White/gold, ORP, Tow Package, 3.55 Gears.

Modifications:
Optima Red Top Battery
Split Fire Spark Plugs
K&N FIPK
Gibson Supertruck Exhaust System
Stepshield door sill protectors
Performance Accesories 3" Body Lift
Superlift 3" lift blocks
Performance Lift Lips
Gabriel Gas Ryder LT VST Shocks
Daystar Front Anti-sway Bar Polyurethane Bushings
Heckethorn Steering Stabilizer
35x12.5R16.5LT BFG All Terrain KO's
16.5x9.75 American Eagle 589's.
McGard Premium Wheel Locks

Photos at: http://www.communicomgroup.com/jmtruck

Almost all my driving (90%) is highway (not interstate) with speeds of about 50-60 miles per hour. That's probably why my mileage is so good. I don't hot-rod very much, either.

Yeah ill be doing alot of highway from work and back. I havent done much highway yet so maybe thats why Im getting 14.4. Im so glad I opted for the 5.4L. The salesman I had tried to sell me a used 4.6L with 30,000 miles and I almost got it because I didn't want to wait the time for factory ordered. IT was well worth the wait. Never felt so much power in my life. I love my truck https://www.f150online.com/f150board/smile.gif

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2001 F-150 5.4L trition,
Regular cab with 8' bed
XLT with Black Clearcoat
4x4 3.55 limited slip
factory cab steps
class III tow package
Factory ordered: 12/5
recieved: 2/22

Mine is pretty consistent at 14 city/17 highway. It was getting 10 combo when new.

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2000 F-150 XL, RC, LB, 5.4L, 4R70W, 3.55LS,
Class III tow, Payload #3, & Convenience pkgs.,
4-wheel disc/ABS, Chestnut/Parchment 40/60,
Ford bedliner w/Paintsaver & gas/wheel/spare locks,
K&N F.I.P.K. w/Outwears pre-filter, Superchip,
Dynomax ultra-flow welded 3" cat-back w/ 3" Y-pipe,
Hellwig front & rear anti-sway bars, Rancho RS 9000s,
Mobil 1, K&N oil filter.

there is no break in period
period ........

Strictly speaking, that's true, but it doesn't explain why most of us notice or trucks getting better mileage after 2 or 3k miles.

ok hotshot trying to be smart fordtech. I was told by dealer to drive at different rpms so engine is broken in at all different speeds rather than consistently driving at one speed.... period.

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2001 F-150 5.4L trition,
Regular cab with 8' bed
XLT with Black Clearcoat
4x4 3.55 limited slip
factory cab steps
class III tow package
Factory ordered: 12/5
recieved: 2/22

and if he said to drive off a cliff would ya

my milage has been pretty consistant.
13-14 in town, 14-17 hwy.
got 13 after spending a whole weekend in 4HI.
The most power in my life, my 5.0 w/ 2.73 gears would spin the rears effortlessly.
I've drove plenty of 7k lb PSD that have 500ftlbs stock. I've really never been impressed w/ this motor. It does fine, better than the 4.6, but 333 ci for 4630lbs really isn't enough motor IMHO. I have thought of going to 3.73's or even 4.10, to have some more low end.
To each his own.

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Dr.(wife says i'm spoiled) Jones.
2000 F-150 5.4L
AUTO,SC-sb 4x4-XLT, 3.55LS, 8.8 front- 9.75 rear, sidesteps, sprayed in liner, 17"wheels ORP, trailer-tow pkg, CD, Cpt chairs, 4whl ABS, Keyless Entry, Airbox silencer removed/K&N, Amsoil(transfercase, motor, rearend(with no friction modifer AND IT WORKS GREAT NOW ), 3" custom dynomax ultra flow catback, as an anniversary gift. With a best of 18.5 MPG.
kjones02@elp.rr.com, strengthbeyondstrength2000@yahoo.com waiting for the 275hp PSD
www.ford-diesel.com , www.fordvschevy.com/ , www.blueovalnews.com/, www.webattack.com, www.thedieselpage.com/cgi-bin/Ultimate.cgi